轴向齿间距和齿腔深度对交错齿迷宫密封泄漏特性影响的数值研究

Effects of the Axial Fins Distance and Cavity Depth on the LeakageFlow Characteristics of the Labyrinth Seal

采用数值求解三维Reynolds-Averaged Navier-Stokes(RANS)方程的方法对典型的燃气轮机交错齿迷宫密封的泄漏特性开展了研究。计算分析了5种轴向齿间距和7种齿腔深度时不同压比下交错齿迷宫密封的泄漏量和流场形态。研究了轴向齿间距、静子面和转子面密封齿腔深度尺寸对交错齿迷宫密封泄漏特性的影响规律。研究结果表明:在齿腔深度保持不变时,轴向齿间距的改变会使得密封有效泄漏间隙发生变化,进而引起泄漏量发生改变。有效泄漏间隙越大,泄漏量越大。轴向齿间距一定时,静子面和转子面齿腔深度对密封泄漏量的影响规律相同。当轴向齿间距为0时,泄漏量随着齿腔深度增加而增大,当轴向齿间距为14mm时,泄漏量随着齿腔深度的增加而减小。研究结果同时验证了交错齿迷宫密封的有效泄漏间隙和齿腔深度是决定其泄漏量的关键几何参数。

The leakage flow characteristics of the typical labyrinth seal of gas turbines were numerically investigated using the three-dimensional Reynolds-Averaged Navier-Stokes(RANS)solutions in this paper.Five kinds of axial fins distance and seven different cavity depths were utilized to analyze the leakage flow rate and field of the labyrinth seal at different pressure ratios.Effects of the axial fins distance and cavity depth of stator and rotor on the leakage flow characteristics of the labyrinth seal were also discussed.The numerical results show that the axial fins distance can lead to variation of the effective sealing clearance and results in change of the leakage flow rate at the fixed of cavity depth.The leakage flow rate increases with increasing the effective clearance.The similar discharge behavior of the labyrinth seal with different cavity depths for the stator and rotor at the constant axial fins distance was obtained.The leakage flow rate of the labyrinth seal increases with the cavity depth increases at the axial fins distance equals 0mm.However,the leakage flow rate decreases with the increasing the cavity depth at the axial fins distance is 14mm.The obtained results also demonstrated that the effective clearance and cavity depth are two critical geometrical parameters on the leakage flow of the labyrinth seal.